Polyfluorinated compositions are used in the preparation of a wide variety of surface treatment materials. These polyfluorinated compositions are typically made of perfluorinated carbon chains connected directly or indirectly to nonfluorinated functional groups capable of further reaction such as hydroxyl groups, carboxylic acid groups, halide groups and others. Various materials made from perfluorinated compositions are known to be useful as surfactants or treating agents to provide surface effects to substrates. Surface effects include repellency to moisture, soil, and stains, and other effects, which are particularly useful for fibrous substrates and other substrates such as hard surfaces. Many such surfactants and treating agents are fluorinated polymers or copolymers.
Most commercially available fluorinated polymers useful as treating agents for imparting surface effects to substrates contain predominantly eight or more carbons in the perfluoroalkyl chain to provide the desired properties. Honda et al, in Macromolecules, 2005, 38, 5699-5705 teach that for perfluoroalkyl chains of greater than 8 carbons, orientation of the perfluoroalkyl groups, designated Rf groups, is maintained in a parallel configuration while for such chains having less than 6 carbons, reorientation occurs. This reorientation decreases surface properties such as contact angle. Thus, polymers containing shorter chain perfluoroalkyls have traditionally not been successful commercially.
EP 1 238 004 (Longoria et al.) discloses a mixture of a fluoroalkyl phosphates and a fluoroacrylate polymer for use in providing stain resistance to stone, masonry, and other hard surfaces.
It is desirable to improve particular surface effects and to increase the fluorine efficiency; i.e., boost the efficiency or performance of treating agents so that lesser amounts of the expensive fluorinated compositions are required to achieve the same level of performance, or so that better performance is achieved using the same level of fluorine. It is desirable to reduce the chain length of the perfluoroalkyl groups thereby reducing the amount of fluorine present, while still achieving the same or superior surface effects.
There is a need for compositions that significantly improve the repellency and stain resistance of fluorinated treating agents for substrates while using lower levels of fluorine. There is also a need for compositions useful as additives in coatings, such as paints, stains, or clear coats, to provide resistance to blocking and enhanced open time extension. The present invention provides such compositions.